Communication method, communication system, node, and program

Abstract

The processing load of a path control message on a node due to a link fault is reduced, a normal routing operation is assured, and the stable continuity of a network is realized. The node having received the path control message transmits the path control message to the adjacent node having transmitted the path control message and at least one or more adjacent nodes on an alternate path.

1 - 28 . (canceled) 
     
     
         29 . A communication method, wherein a node having received a route control message transmits the route control message to a neighboring node having transmitted said route control message, and at least one neighboring node or more on an alternate route. 
     
     
         30 . A communication method according to  claim 29 , wherein the node having received the route control message associated with a link fault compares a fault route in which the fault has occurred with the selected alternate route by employing an evaluation function F( ), and stops transmission of the route control message when F(alternate route)≧F(fault route). 
     
     
         31 . A communication method according to  claim 30 , wherein when the node having stopped the transmission of said route control message associated with the link fault receives the route control message associated with link recovery, it stops the transmission of the route control message associated with link recovery. 
     
     
         32 . A communication method according to  claim 29 , wherein the node transmits the route control message to the neighboring nodes when no alternate route exists. 
     
     
         33 . A communication method according to  claim 29 , wherein the node having detected the link fault transmits the route control message to the neighboring nodes when a value indicative of a degree of the link fault exceeds a predetermined threshold. 
     
     
         34 . A communication method according to  claim 29 , wherein said node having detected the link fault transmits the route control message to the neighboring nodes on at least one alternate route or more. 
     
     
         35 . A communication system that is configure of at least one node or more, wherein said node comprises:
 a storage unit that stores alternate routes; and   a route control message transmission unit that receives a route control message, selects at least one alternate route or more from among the alternate routes stored in said storage unit, and transmits the route control message to the neighboring nodes on the selected alternate route, and the neighboring node having transmitted said route control message.   
     
     
         36 . A communication system according to  claim 35 , wherein said route control message transmission unit compares a fault route in which a fault has occurred with the selected alternate route by employing an evaluation function F( ), and stops transmission of the route control message associated with a link fault when F(alternate route)≧F(fault route). 
     
     
         37 . A communication system according to  claim 36 , wherein when said route control message transmission unit has stopped the transmission of said route control message associated with the link fault, it stops the transmission of the received route control message associated with link recovery. 
     
     
         38 . A communication system according to  claim 35 , wherein said route control message transmission unit transmits the route control message to the neighboring nodes when no alternate route being selected exists. 
     
     
         39 . A communication system according to  claim 37 :
 wherein said node comprises a link fault detector for detecting the link fault, and a comparer for comparing a value indicative of a degree of said detected link fault with a predetermined threshold; and   wherein said route control message transmission unit transmits the route control message to the neighboring nodes when said value indicative of a degree of the detected link fault exceeds said predetermined threshold.   
     
     
         40 . A communication system according to  claim 35 , wherein said route control message transmission unit selects at least one alternate route or more from among the alternate routes stored in said storage unit when its own node detects the link fault, and transmits the route control message to the neighboring nodes on the selected alternate route. 
     
     
         41 . A node, comprising:
 a storage unit that stores alternate routes; and   a route control message transmission unit that receives a route control message, selects at least one alternate route or more from among the alternate routes stored in said storage unit, and transmits the route control message to neighboring nodes on the selected alternate route, and the neighboring node having transmitted said route control message.   
     
     
         42 . A node according to  claim 41 , wherein said route control message transmission unit compares a fault route in which a fault has occurred with the selected alternate route by employing an evaluation function F( ), and stops transmission of the route control message associated with a link fault when F(alternate route)≧F(fault route). 
     
     
         43 . A node according to  claim 42 , wherein when said route control message transmission unit has stopped the transmission of said route control message associated with the link fault, it stops the transmission of the received route control message associated with link recovery. 
     
     
         44 . A node according to  claim 41 , wherein said route control message transmission unit transmits the route control message to the neighboring nodes when no alternate route being selected exists. 
     
     
         45 . A node according to  claim 41 , comprising a link fault detector for detecting the link fault, and a comparer for comparing a value indicative of a degree of said detected link fault with a predetermined threshold, wherein said route control message transmission unit transmits the route control message to the neighboring nodes when said value indicative of a degree of the detected link fault exceeds said predetermined threshold. 
     
     
         46 . A node according to  claim 41 , wherein said route control message transmission unit selects at least one alternate route or more from among the alternate routes stored in said storage unit when its own node detects the link fault, and transmits the route control message to the neighboring nodes on the selected alternate route. 
     
     
         47 . A computer readable storage medium storing computer instructions for causing a computer executing the instructions, said instructions causing said computer to implement a method comprising:
 an alternate route selection process of, when receiving a route control message, selecting at least one alternate route or more from among alternate routes stored in a storage unit; and   a route control message transmission process of transmitting the route control message to neighboring nodes on the selected alternate route, and the neighboring node having transmitted said route control message.   
     
     
         48 . A communication method, wherein a node having received a cancel route information transmits arrivable route information to a neighboring node having transmitted the cancel route information. 
     
     
         49 . A node, comprising a means for, when receiving a cancel route information, transmitting arrivable route information to a neighboring node having transmitted the cancel route information.